Internal combustion engine



1935- R. N. DU BOIS INTERNAL COMBUSTIOii ENGINE Filed Aug. 25, 1930 2 Sheets-Sheet l A TTORNE Y INTERNAL COMBUSTION ENGINE Filed Aug. 25, 1930 2 S heetsSheet 2 A TTORNE Y.

Patented F eb. 12, l935 UNITED STATES.

INTERNAL COMBUSTION ENGINE Ralph N. Du Bois, Detroit, Mich., assignor, by mesne assignments, to Continental Aircraft Engine Company, a corporation of Delaware Application August 25,

13 Claims.

My invention relates to engines and more particularly to an engine cowl structure adapted for assembly with air cooled internal combustion engines of the type provided with a plurality of radially extending air cooled cylinders.

Experience has shown that the low-drag cowling as applied to radial engines has increased the speed of the plane and for this reason such engine cowl structures are now quite widely used. However, it is difficult to service engines equipped with this type of cowling, such as adjusting valves, changing spark plugs, etc., as it is necessary to remove the ring cowling before such adjustment can be made.

One of the objects of my invention is to provide an improved low-drag cowling for an aircraft radial air cooled engine that may be economically manufactured and readily assembled with an engine of the aforesaid type.

Andther object of my invention is to overcome the servicing diificulties in connection with engines of the foresaid type equipped with lowdrag cowling by providing a segmental cowling structure that may be readily attached to the engine and which is so constructed that the segmental cowl sections can be independently re- -moved when it is necessary for access to be had to any of the engine cylinders for making repairs or adjustments.

Other features and objects of my invention will be more apparent as the description progresses in which I described a preferred embodiment of my invention as illustrated in the accompanying drawings, and in which:

Figure 1 is a front elevational view of a radial air cooled aircraft internal combustion engine equipped with a low-drag cowling constructed in accordance with my invention,

Figure 2 is a fragmental detail view partly in section of one of the segmental cowl sections and showing the means for. fastening the same to the engine,

Figure 3 is a side elevational view ,of the engine cowling showing the relation thereof with an engine,

Figure 4 is a sectional view taken on the line 4-4 of Figure 3 showing in detail the construction of one of the segmental cowl sections,

Figure 5 is a fragmentary bottom plan View of one of the cowl sections,

Figure 6 is a fragmentary plan view of the front edge of the segmental cowl sections showing how the same may be fastened together, and

Figure '7 is a detail sectional view taken on the line 7-7 of Figure 6.

An aircraft engine for which my novel cowling structure is adapted to be used, comprises a crankcase 5 in which is supported the crankshaftfi, and a plurality of cylinders 7 extending radially outward from the crankcase and 1930, Serial No. 477,550

Conseof streamlined engine cowling in order to obtain r the best possible performance from their product. I have provided an engine cowling A suitable for use with a radial air cooled aircraft internal combustion engine. The cowling structure comprises a structure composed of a plurality of segmental cowl sections 10, said sections arranged in a ring around the engine. Each of said sections is constructed with a pocket portion 11 surrounded by a flange 12, said flange being adapted to seat on top the side and end walls of the rocker box housing 13, the pocket portion 11 serving as a rocker box cover. Any form of securing means such as screws 14 may be employed to secure the segmental cowl sections to the rocker arm boxes, said boxes being carried by the cylinder structure in the usual manner.

I prefer to divide the ring into rather smallseg ments' and to secure a separate segment to each rocker box, though obviously larger segments may be found to be more desirable in some instances, as for instance a segment of a size suflicient to enclose both rocker boxes of a; cylinder. However, for purposes of illustrating the invention,

, each cowl segment is attached to a separate rocker box. These cowl segments are provided with the pocket portion 11 adjacent the rear thereof and are arranged to project forwardly of the cylinders. The segments are curved longitudinally of the crankshaft axis and thus the front portions of the segments are projected inwardly as well as forwardly ,of the cylinders and when the segments are assembled together to form a ring, it will be noted that the cowl is streamlined. If found desirable the front portions of the cowl segments may be secured together by any suitable fastening device, one of which is illustrated in Figures 6 and 7. A U-clamp 30 is slipped over the front edge of the segments, and pins 31 are passed through registering perforations in the segments and clamp, a lock device such as a safety pin 32 being passed through the pins 31 to lock the pins 31 in place. The necessity for securing the segments to each other depends largely on the rigidity of the material out of which the segments are constructed, and I find that it permitting access to be had to the interior of.

the rocker box to which said segment is secured. A segmental cowling such as I have illustrated may be economically and readily manufactured and assembled to the "engine, and furthermore the combined ring cowling segment and rocker box cover may be removed with no more, labor than was required to formerly remove the rocker box cover alone. Such cowling structures are usually referred to as low drag cowlings, because such streamlined cowlings offer a minimum of resistance to the passage of a plane equipped with radial air cooled aircraft engines through the air.

Although I have illustrated but one form of my invention and have described in detail but a single application thereof, it will be apparent to those skilled in the art to which my invention pertains, that various modifications and changes maybe made therein without departing from the spirit of my invention or from the scope of the ap-' pended claims.

What I claim as my invention is:

1. An engine cowl structure for aircraft having an air cooled internal combustion engine of the type provided with a plurality of radially extend ing air cooled cylinders, and comprising a plurality of removable segmental combined cowl sections and rocker box covers.

2. An engine cowl structure for aircraft having an air cooled internal combustion engine of the type provided with a plurality of radially extending air cooled cylinders having rocker box'housings, and comprising a plurality of cowl sections secured to said cylinders and forming covers for said rocker box housings.

3. An engine cowl structure for 'aircraft having an air cooled internal combustion engine of the type provided with a'plurality of radially extending air cooled cylinders having rockerbox housings, and comprising a plurality of removably supported segmental cowl sections each section forming a cover for at least one of said rocker box housings.-

4. An engine cowl structure for aircraft having an air cooled internal combustion engine of the type provided with a plurality of radially extending air cooled cylinders having rocker box hous ings, and comprising a plurality of segmental cowl sections each having the rear end portion constructed to form a rocker box cover, and means for removably securing said sections to the rocker boxes, the said sections having portions extending forwardly of said cylinders.

5. An engine cowl structure for aircraft having an air cooled internal combustion engine of the type provided with a pluralityof radially extending air cooled cylinders having rocker box housings, and comprising a plurality'of segmental cowl sections removably supported independently of each other, each section forming a rocker box cover and having a portion thereof extending forwardly of said cylinders.

6. An engine cowl structure for aircraft having an air cooled internal combustion engine of the type provided with a plurality of radially extending air cooled cylinders having rocker box housings, and comprising a plurality of segmental cowl sections each having a portion forming a rocker'box cover and an arcuate portion extendingforwardly and inwardly of said cylinders,'said cowl sections removably secured to said rocker boxes.

7. An engine cowl structure for aircraft having an air cooled internal combustion engine of the type provided with a plurality of radially extending air cooled cylinders and an exhaust manifold, and comprisinga plurality of segmental cowl sections separate from the exhaust manifold and extending forwardly and rearwardly of said exhaust manifold, the rear portion of said sections formingrocker box covers and secured to the cylinders'the forward portion of said sections overhanging said exhaust manifold and being radially spaced outwardly therefrom; the said sections being fastened together adjacent their forward end.

8. An engine cowl structure for aircraft having an 'air cooled internal combustion engine of the type provided with a plurality of radially extending air cooled cylinders, and comprising a plurality of removable segmental combined cowl sections and rocker box covers, said sections being provided with countersinks, and bolts passing through said sections into screwthreaded connection with said engine and'having their heads seated in said countersink's.

9. In an engine of the type having a plurality engine .cowl structure surrounding said engine and formed of sections adapted to be separately secured to and removed from said engine, said .of radially extending air cooled cylinders, an I removed from said engine and 'each'including a rocker box cover portion removable therewith.

11. In an engine having a plurality ofradially extending air cooled cylinders each having ,a valve chamber and a seat for a cover, asectional cowl structure surrounding the engine and comprising a plurality 'of'cooperating segmentalcowl sections each including a cover portion, and

means for securing said cover portion to said seat.

12. In an engine having a plurality of radially extending air cooled cylinders eachhaving a valve chamber and a seat for a cover, a cowl structure surrounding the engine and comprising.

a plurality of cooperating segmental cowl sections detachably secured together and each'hav- 7 ing a cover portion at one end, and means for detachably securing each of said cover portions to one of said seats.;

13. In an engine having a plurality of radially extending air cooled cylinders each having a valve. I

chamber and a seat for a cover, a cowl structure surrounding the engine and comprising a pmrality of cooperating segmentalcowl sections detachably secured together .and each having a cover portion at one end formed integral therewith, and means for securing each of said cover 1 portions to one of said seats.

RALPI-I N. no 1301s. 

